Apparatus for delivering combustible mixture to an internal combustion engine



APPARATUS FOR DELIVERING COMBUSTIBLE MIXTURE TO AN INTERNAL COMBUSTIONENGINE July 1, 1958 B. c. PHlLLlPS 2,841,372

Filed June 4, 1956 6 Sheets-Sheet 1 60 2 6 I x I 26 I -----4 \A' J 1 Q QI 5 INVENTOR BERNARD C. PHILLIPS Q W ATTORNEY July 1, 1958 B. c.PHILLIPS APPARATUS F OR DELIVERING COMBUSTIBLE MIXTURE TO AN INTERNALCOMBUSTION ENGINE 6 Sheets-Sheet 2 Filed June 4, 1956 INVENTOR BERNARDc. PHILLIPS BY Mt? ATTORNEY y 1958 B. c. PHILLIPS 2,841,372

APPARATUS FOR DELIVERING COMBUSTIBLE MIXTURE TO AN INTERNAL COMBUSTIONENGINE Filed June 4, 1956 6 Sheets-Sheet 5 INJ ENTOR BERNARD C. PH/LL/PSBY 2414/7 & MW I ATTORNEY y 1958 B. c. PHlLLlPS 2,841,372 APPARATUS FORDELIVERING COMBUSTIBLE MIXTURE TO AN INTERNAL COMBUSTION ENGINE FiledJune 4, 1956 6 Sheets-Sheet 4 INVENTOR BERNARD C. PHILLIPS y 1958 B. c.PHILLIPS 2,841,372

APPARATUS FOR DELIVERING COMBUSTIBLE MIXTURE.

TO AN INTERNAL COMBUSTION ENGINE Filed June 4, 1956 6 Sheets-Sheet 5INVENTOR BERNARD C. PHILLIPS Mmw y 1958 B. c. PHILLIPS 2,841,372

APPARATUS FOR DELIVERING COMBUSTIBLE MIXTURE.

TO AN INTERNAL COMBUSTION ENGINE Filed June 4, 1956 6 Sheets-Sheet 6CAPILLARY SEAL FOR VARIOUS CONDITBDNS.

* DDTTED LlNES SHOW OPERATING DEPRESSION.

2.0 MAIN ADJ. I TURN.

CHAMBER FUEL SUPPLY #60 (.040) DRILL.

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E 2.0 I NOZZLE BORE #56 (.046) DRILL. w MAIN AI .I'.= ITURN. 2 uu It! I.W

l I i 5 I I i .Ol .02 .03 .94 .85 D6 .07 .08 FUEL SUPPLY FROM RESfiEJMRDflfl. IN INtHES H5 2 4 INVENTOR:

Emmy LTPHJLL TF5.

ATTORNE f atented July 1, 135-8 APPARATUS FOR DELIVERING COMBUSTIBLE T0AN INTERNAL COMBUSTION ENGINE Bernard C. Phillips, Toledo, one, assignorto The Tillotson Manufacturing Company; Toledo, Ohio, 21 corporation ofOhio Application June 4, 1956, Serial No. 589,170 17 Claims; c1. 261-41)This invention relates to fuel feedingand cnarge forming apparatus foruse with internal combustion engines and more especially to apparatusfor delivering a fuel and air mixture to an internal combustion engineirrespective of the relative position of the engine and charge formingapparatus.

Internal combustion engines, and particularly those of the two cycletype, are being utilized extensively for powering lawn mowers, chainsaws, small'boats and for other similar uses where the engine and chargeforming device are sometimes-tilted to extreme angular positions.Engines for driving chain saws must be'adaptable for operation in allangular positions including inverted position.

The conventional type of charge forming device embodying afloat-actuated fuel control valve is wholly unsuitable for use withengines which are to be operated in extreme angular positions. Chargeforming'devices embodying diaphragm controlled fuel supply means havebeen developed and have been used' but such devices heretofore employedhave been extremely critical in operation and adjustment.

The present invention embraces an apparatus for de livering or feeding afuel and air mixture to an internal combustion engine irrespective ofthe relative angular position of'the engine.

Another object of the invention relates 'to a system of supplying liquidfuel to a mixing passage of a charge forming apparatus incorporatingmultiple fuel delivery channels whereby. the surface tension andcapillary. characteristic of liquid fuel in the channels is renderedeffective to restrict or prevent entrance of air into a main fueldelivery system from the mixing passage when fuel is being deliveredinto the mixing passage through a secondary system for engine idlingandlow speed purposes.

Another object of the invention is the provision of a charge formingdevice of acharacter embodying a 'diaphragm actuated fuel flow controlmeans wherein the diaphragm is instantly responsive to minute variationsin pressure in the mixing passagewhereby 'the fuel. requirements of theengine are satisfied at all engine speeds.

Another object is the provision of a diaphragmtype of charge formingdevice wherein fuel is delivered into the mixing passage solely byaspiration established through engine operation and with aminimumofdifferential pressure.

Another object of the invention is theprovisionof a carburetor or chargeforming device of the diaphragm type having fuel delivery channelsopening int'o'a mixing passage for high speed and engine idling and lowspeed purposes wherein the high speed fuel delivery arrangement embodiesa restricted zone or zonesin which the fuel forms an effective barrieror seal preventing air bleeding through the high speed fuel deliverysystem without the use of check valves or othermechanical means.

Another object of the invention is'theprovi'sion of'a diaphragm typecarburetor or charge forming device wherein the fuel passages are soarranged as to utilize the capillary action and surface tension andmeniscus effect of the liquid fuel as a nozzle check or valve means toprevent back bleeding of air from the mixing passage into the fuelchamber under idling conditions as well as during high speed operationsof the engine.

Another object of the invention is the provision of a diaphragm type ofcarburetor embodying a guide arrangement and mounting construction forthe diaphragm wherein a relation is established between the guide meansand openings in a peripheral zone of the diaphragm re ceiving the guidemeans setting up a flexibility in the central zone of the diaphragmwhereby a regulated or controlled amount of dish or concavity of thediaphragm is obtained obviating the necessity of forming circularconvolutions in the diaphragm.

Another object of the invention is the provision of a diaphragm typecharge forming device wherein fuel is delivered into the mixing passagesolely by engine aspiration at a minimum of subatmospheric or reducedpressure whereby a fluid seal established by the liquid fuel in thepassages or channels of the main fuel delivery system in the chargeforming device is not interrupted or fractured when the engine isoperating under idling or low speed conditions when fuel is supplied tothe mixing passage through a secondary fuel delivery system.

Another object of the invention is the provision of a carburetor of thediaphragm type wherein the distance or dimension between the diaphragmand the mixing passage is maintained at a minimum providing a minimumlift whereby fuel is delivered into the mixing passage by aspirationunder comparatively small differential or subatmospheric pressures. I

Another object of the invention resides in a combined fuel deliverymeans and mixture forming apparatus for an internal combustion enginewherein a flexible wall or diaphragm of a pumping or pulsating chamberis connected through a suitable duct with the crankcase of the enginewith which the charge forming apparatus is used whereby varyingpressures in the engine crank caseare utilized for vibrating or movingthe flexible diaphragm, providing a motivating means for flowing liquidfuel from a supply to the charge forming apparatus.

A further object of the invention is the provision of a diaphragm typecarburetor or charge forming device adaptable for use with anindependent fuel supply means or which may form a unit or component of acombined charge forming apparatus and fuel pumping or supply means. 1

Further objects and advantages are within the scope of this inventionsuch as relate to the arrangement, operation and function of the relatedelements of the structure, to various details of construction and tocombinations of parts, elements per se, and to economics of manufactureand numerous other features as wiil heapparent from a consideration ofthe specification and 'drawingof a form of the invention which may bepreferred, in which:

Figure'l is a side elevational view illustrating one form of combinedcharge forming device and'fti'e'l feeding meansof the invention;

Figure 2 is'a top plan view of the arrangement shown in 'Figure' 1;

Figure 3 is an end view of the arrangement shown in Figure 1;

Figure 4 is 'a view similar to Figure 3 showing the charge formingdevice or carburetor per se;

Figure 5 is a longitudinal sectional view' taken substantially on theline 55 of Figure 2;

Figure 6-is a transverse sectional view through the carburetor, the viewbeing taken substantially on the line 6-6 of Figure 2;

' of the character disclosed may be used..

Figure 7 is a detail sectional view through the carbu retor, the viewbeing takensubstantially on the line 77 of Figure 1;

Figure 8 is a detail sectional view or, the view being takensubstantially on the line 8-8 of Figure 1;

Figure 9 is an enlarged schematic sectional view through the chargeforming device and fuel feeding means illustrating the interrelation ofthe various components of the construction; 7 r Figure 10 is ahorizontal bottom plan view of the charge forming device with thediaphragm removed illustrating one arrangement of fuel channels andmetering means for supplying liquid fuel to a main orifice and idlingand low speed fuel orifices for delivery into the mixing passage; 7

Figure 11 is a view similar to Figure 10 showing a modified arrangementof fuel channels and metering means for supplying fuel to a main orificeand the idling and low speed orifices;

Figure 12 is' a view similar to Figure a further arrangement of' fuelpassages'a'nd metering means for supplying fuel to a main, idling andlow speed orifices;

Figure 13 is an elevational view of the combined carburetor and fuelfeeding means, the latter being shown in section; V

Figure '14 is a plan view of the pumping diaphragm or element of thefuel feeding means; i

Figure 15 is a view taken substantially on the line 1515 of Figure 13;

Figure 16'is a view taken substantially on the line 1616 of Figure 13;

' Figure 17 is a sectional view takensubstantially on the line 1717 ofFigure 13; Y

Figure 18 is a fragmentary detail sectional'view taken substantially onthe line 1818 of Figure 15;

Figure 19 is a fragmentary detail sectional view taken tially on theline 2tl-20 of Figure 15; I

Figure 21 is a fragmentary sectional view taken substantially on theline 2121 of Figure 16;

Figure 22 is a fragmentary sectional view taken substantially on theline 22'22 of Figure 16; V

Figure 23 is a view taken substantially on the line 23- -23 of Figure 13and illustrating the method of mounting the diaphragm forming a-wall ofthe carburetor fuel chamber to secure a concave or dished configurationof the diaphragm; a V

Figure 24 is a graph'showing the strength-of the capillary seal undervarious operating conditions, and

Figure '25 is a'diagrammatic sectional view showing a fuel adjustingmeans. a 7

{While the charge formingvand fuel feeding apparatus of the presentinvention are illustrated as particularly constructed andadaptedtfortcarrying out the method of delivering fuel to an internalcombustion engine of the so-called two cycle type, it is to beunderstood that the arrangement of the invention may be utilized withother types of internal combustion engine whe'reever a diaphragm type ofcarburetor ortcharge'forming apparatus It should be further understood,that the inventionembraces a particular interrelation and coordinationof com-. ponents of the charge forming device whereby aso called 7 freeposition operation'is obtained, that isfwherein the through thecarburetcharge forming device or carburetor component is of the idiaphragm type and is constructed with a minimum of 10 illustrating fuellift distance whereby fuel may be readily delivered into a mixingpassage to be mixed with air and thence into the crankcase of a twocycle internalcombustion engine by reason of the aspirating efiect ofvaryingpres suresrin the engine crankcase.

Figures 4 through 8 inclusive illustrate .a formof charge forming deviceof the invention without the fuel 7 feeding pump, and it is to beunderstood that Figures 1 through 8 and 10 through 13 are illustrativeof the same carburetor component, Figure 9 illustrating in schematicform the combined carburetor construction and the fuel.

feed means or pump for delivering fuel to the carburetor.

The charge forming device or carburetor component of the construction isinclusive of a body 10 formed with a mixing passage 12, the passageincluding a Venturi 14 into which fuel is delivered for admixing withair admitted through an air inlet 15. A disk type valve 17 mounted uponan operating shaft 18 is disposed in the inletpassage 15 and is adaptedfor controlling the amount ofair admitted to the mixing passage 12formed in the body'10. Mounted upon an end of the shaft 18 projectingexteriorly of the body 10'is an arm 20 for manipulating or regulatingthe position of the choke or air valve 17.

Thecarburetor body 10 is provided with a flange portion 22 which isadapted to be secured to a boss portion flange 27 to be secured to anair filter or cleaner (not shown). 1

The body 10 of the charge forming device is ifor'med with a fuel chamberor passage 30, and a flexible member or'diaphragm 32 forms one wall ofthe chamber or passage 30 as shown in Figures 5 and 6. An annular gasket31 is disposed adjacent one face of the flexible diaphragm 32 as shownin Figures 5 and 6. In the arrangement of combined carburetorandtfuelfeeding'or pumping means of the character illustrated in Figures1,3 and 13, the

gasket 31- is engaged by a member or component "10d 7 forming part ofthe fuel pumping means. I

In the arrangement of the charge forming device shown in Figures 4, 5,and 6 wherein the fuel isdelivered to the charge forming device bygravity or by pumping-means disposed remotely of the charge formingdevice, the g'asket' 31 is engaged by a cover plate 36. In this'form,the

cover plate 36'which may be formed of sheet metal or molded resinousplastic and has a peripheral planar.

portion 37 provided with openings adapted to receive screws 39 forsecuringthe cover plate 36 to'the'carburetor body 10.' V t The coverplate 36 isformed with ,a depressed central portion providing a space40'to accommodate reciprocatory movements or vibrations of the diaphragm32, the space 40 being vented to the atmosphere by'means of an opening41; The diaphragm 32 is made-of very, thin highly flexible clothtas,'for example, nylon fabric-impregnated with a suitablc'coating torender the diaphragm J V impervious. Y

Heretofore it has been a'practice to form" diaphragms with one or moreconcentric annular convolutions in charge forming device may besatisfactorily and effectively used in various angular; a's'jwell a'sinvert'ed positions and supply fuel to a mixing passage-to maintain theengine in 7 order to provide for flexing pr 'reciprocatory movements ofthe diaphragm. A feature of this invention resides in v the provision ofa planar diaphragm and a means of mounting the same whereby therequiredamount of dish" diaphragm 32 is formed with an equal number of 'open- Vings 46 having the a same circumferential spacing ;as the pins 44 butthe openings 46 are normaliy spaced at greater radial distances from thecenter of the diaphragm than .the pins or projections 4 The diaphragm 32is fitted into place with the openings 46 received over the pins 44, andthis operation forces or flexes the central zone of the iaphragminwardly in a loose or wavy formation which establishes the requiredamount of dish or concavity for the diaphragm to facilitatereciprocatory motions or vibrations without necessitating stretching orpulling of the diaphragm. This arrangement not only facilitates the useof a comparatively thin, highly flexible diaphragm but also avoids oreliminates the necessity for me preshaping of annular convolutio-ns inthe diaphragm. The extremely flexible and very thin diaphragm is highlysensitive to minute variations or changes in pressure in the fuelchamber or passage 34) thus providing an ehicient and uniform deliveryof liquid fuel into the mixing passage.

Fuel from the chamber or passage 30 is delivered into the restrictedzone or choke band 47 of the Venturi 1d through a main or primaryorifice, nozzle or tubular passage 43 supplied with fuel throughpassages and metered by suitable means as hereinafter described. Alsoopening into the wall of the mixing passage is a secondary fuel deliverysystem including an idling orifice 5t} and a second orifice 52, thelatter being used for low speed engine operations. The manner ofsupplying fuel to these orifices will be hereinafter described.

Disposed in the outlet zone 54 of the mixing passage 12 is a throttlevalve 56 of the disk type which is mounted upon a transversely extendingshaft 58, the shaft being rotatable to vary the position of the throttlevalve 56 for controlling the admission of fuel and air mixture into theengine crankcase to regulate the speed of the engine. An arm 6% ismounted on one end of the shaft 58 provided with a roller 62 adapted tobe engaged by a suitable throttle actuating means (not shown).

Secured to the opposite end of the shaft 58 is an L- shaped arm 64. Thecarburetor body is provided with a projecting portion 66 having athreaded opening to receive a threaded member or screw 68. The extremityof the screw 68 forms a stop means engageable with a portion of theL-shaped arm 64 to limit the closing movement of the throttle valve 56.A coil spring 70 surrounds the threaded member 68 and bears against theprojection 66 and provides sufiicient friction to hold the threadedmember 68 in adjusted position.

Means is provided in the charge forming apparatus for controlling theflow of fuel from a supply into the fuel chamber or passage 3%. Thediaphragm control arrangement for the fuel inlet valve is shown indetail in Figures 6 and 9. The fuel inlet passage in the carburetor bodyas shown in Figure 6 is arranged to be connected to a fuel pump situatedremote from the carburetor or is adapted to receive fuel by gravity froma supply tank.

When this system of delivering fuel to the charge forming apparatus isutilized, the diaphragm 32. is secured to the carburetor body by meansof the plate 36 as shown in Figure 6. When a fuel feeding means isintegrated or combined with the charge forming apparatus as particularlyshown in Figures 1, 3, 9 and 13, a modified form of fuel inlet channelarrangement into the charge forming device is employed as hereinafterexplained.

The carburetor body it) is formed with an elongated recess 72 forming apart of the fuel passage or diaphragm chamber and is adapted toaccommodate a lever or lever member 74 pivotally supported upon a pin75. The pin 75 has a head portion 76 projecting exteriorly of thecarburetor body as shown in Figures 3 and 4 to facilitate assembly andremoval of the pin or shaft 75. The diaphragm 32 is provided at itsopposite sides with disks 7% and '7) which are held together by means ofa headed member The head of member 80 is in continuous operationalengagement with the end zone of arm 81 of the lever member 74. A coilspring 83 is contained in a bore adjacent the recess 72, the lower endengaging the lever arm.81 and being held in place by means of astruck-up projection 84 formed on the lever member.

Threaded into a bore formed within the carburetor body 1% is a fitting86. Slidably disposed in a bore formed in the fitting 86 is a valvemember 88 of polygonally shaped cross-section. The polygonally shapedcross-section of valve member 88 facilitates flow of liquid fuel alongthe facets of the valve body into the fuel passage or chamber 3d. Thevalve member 88 is formed with a cone-shaped extremity or valve portion90 which cooperates with a disposed in the upper end zone of the fittingThe valve seat 91 is preferably formed of a resilient material as forexample a synthetic material such as neoprene or other material which isnot subject to deterioration contact with hydrocarbon fuels. The openingin the valve seat 91 should be of comparatively small diameter so thatthe fuel pressure actingagainst the cone shaped valve portion 9% isreduced to a minimum.

As shown in Figure 6, the opening in the valve seat 91 is incommunication with interconnecting ducts 93 and 94. When the chargeforming apparatus or carburetor is used with a gravity fuel supply or afeeding means positioned remotely with respect to the carburetor, theverticaliy arranged duct 94 is closed by means of a plug 96. Theentrance of the fuel duct 93 may be threaded to accommodate the threadedextremity of a fuel supply tube 8 as shown in Figure 6.

it should be pointed out that the fuel chamber or passe "e is not ventedto the atmosphere and fuel chamber or passage is delivered into themixof the carburetor by engine aspiration either 1. By reason of thefact that fuel is delivered into the mixing passage solely by aspirationeffect of the reduced pressure therein acting upon the fuel chamber 3-9,there is no predetermined or defined fuel level in the chamber 34 Asfuel is delivered into the mixing passage under the influence of reducedpressure transmitted through the fuel orifices to the fuel chamber 30,the flow of fuel into the mixing passage depletes the supply in the fuelpassage or chamber 3%,, further decreasing the pressure in the chamberThis reduction in pressure in chamber 3% causes body and into the fuelchamber 3% The flow of fuel into the chamber slightly increases thepressure in the chamber 3% and, under the influence of the expansivecoil spring 83, t1 lever member 74 is swung about the pivot shaft 75 ina clockwise direction as viewed in Figure 6 as the diaphragm 32 moves oris fiexed downwardly under the influence of the increase in pressure inthe chamber Sli The movement of lever member 74 elevates the valve body88 and the valve portion 99 again closing the opening in the valve seat91 to interrupt flow of liquid fuel into the chamber 33 until thecontinued delivery of fuel into the mixing passage further reduces thepressure in the fuel passage or chamber 36. In actual practice duringengine operation it is found that a balance is substantially maintainedwhereby the rate of flow of fuel past the valve $5.: is substantiallyequal to the rate of delivery of the fuel from the chamber 30 into themixing passage E2, the control valve being in slightly open positicnduring most of the period of engine operation.

The combined fuel feeding means and charge forming V 7 apparatusis'illustrated in Figures 22 inclusive. When the carburetor isintegrated or combined with a fuel feeding means, the threaded entrancezone'of the fuel duct 93 shown in Figure 6 is closed by means of a plugor other form of closure.

The fuel pumping or fuel feeding arrangement includes a pump bodyconstruction formed by comp onents' or e members 100, 101 and 102. ;Theclosure member 102,

1, 3, 9 @113 through which may be formed of molded nylon .orother material is provided with a tubular projection 104 adapted to be connectedto a fuel supply tank (not shown) by means of a flexible tube 106 shownin Figure 13. "The member 101 is formed with a circular recess arrangedto receive the peripheral edge zone of a fuel filter or strainer Agasket 108 of annular shape is also fitted into the recess and isengaged by a circular peripheral portion'of SP1 is) 1 the closure.member 7102 for retaining the strainer in position. The member 101 isformed with'a depending boss 109 formedwith a threaded bore adapted tore ceive'a screw 111 for holding the closure member 182 :in position. Asealing gasket 112 is interposed between the head of the screw and theclosure 102.

The projection 104 is provided with an inlet passage 114 which conveysfuel from the supply into a sump or chamber 115 formed by the closuremember 102.. Thus any foreign matter strained from the fuel by thescreen or filter 107 is collected upon the inner surface of the closuremember 102. For purposes of illustration Figure "9 exemplifies a sectionthrough'the fuel pumping construction and is semischematic in characterto better show the valves and fuel passages in the pumping arrangement.

in the arrangement of the invention embodying'the fuel pumping means asan integrated component of the charge forming apparatus, the member 100is in direct engagement with thesealing gasket'31 adjacent the diaphragm32 forming a wall of the fuel chamberfii] in the carburetor. Disposedbetween the members or components 100 and 101 is a flexible diaphragm orfuel pumping element 118 which is formed of flexible impervious materialsuch as synthetic rubber or cloth such as nylon impregnated or coatedwith a material which is resistant to deterioration by hydrocarbonfuels.

The pump body member 1110 is provided with a plurality ofopenings 121and the body member 101 provided with a plurality of openings 122 which,when the member 101) and 1.01am in assembled relation, are in alignedcondition and adapted to receive securing screws 123 which extend intothreaded openings 124 formed in the carburetor body 10 as shown inFigure 10. The screws 123 also pass through openings 125 formed in aperipheral'zone of the pumping diaphragm 118. e

As shown in Figures 13 and 15,7the central zone. of. the pump bodymember 100 is formed with a spherically shaped recess or depression 127forming a pumping chamber, and the pump body member 101 is formedalternately increase and decrease municated to the chamber 127 throughthe passages 133, .132 and'131 to eflect a pulsating or pumping actionof the. diaphragm 118 which sets up a pumping action in the fuelchamber. 129. by varying .the volume of the latter.

In the present arrangement, the valve means for controlling the flow ofliquid fuel into and away from the fuel chamber 129 in the pumping meansare integral components 'of' the diaphragm 118. As particularly shown inFigure 14, the inlet valve 136 and the outlet valve 138 are formed bypunching or removingmaterial of the diaphragm providing spaces V140 and141,.the vaive portions'136 and 138 being shaped asftongues adapted tobe flexed at the hinge orzone of juncture of the valve portions withtheremainder ofthe diaphragm The valve portion 136 controls the port 143shown' in Figures 13 and 16 which is iu communication with the chamber"above the strainer 107 formed in the pump body member 101 as shown inFigure 9. The outlet valve member 138 is adapted to cooperate with aport or passage lladapted to, conveyliquid fuel out of the fuel chamber129.

The bodymember 100 is formed with a recess 146 V which accommodatesmovement of thelvalve member 135 and forms a channel to facilitateflowof fuel-from theport 143 through. the passage 148 into the fuelchamber'129." The pump body member 100 is formed with a second recess150 to accommodate movement of the, valve member 138 controlling flow ofliquid fuel through the port144 into a vertically disposed outlet orpassage 152formed in the" body member 100. .The fuel outlet passage 152is' in registration with'thef fuel passage 94,

shown in Figure 9, formed in the body portion 10 of the carburetor, Inthe arrangement embodying the fuel feeding means hereinabove described,the plug or cap 96 shown in the fuel passage 94 in Figure 6 iseliminated so that fuel may flow direct from the fuel pumping cbam:

her 129 through the port'144, the recess 150 and passages 152 and 9.4 tothe zone above the fuel flow control 'valve 90 shown in Figure 6. 7 I 7j The pump body member 100 is'formed at its upper portion with a shallowcircular chamber 155 adapted to accommodate flexure or reciprocatorymovements of the with a spherically shaped recess or depression formingor munication with a passage 133 form-ed in the flange 22 of thecarburetor body 10. i

The passage 133 is shown in Figure 3 and isarrangcd V to be incommunication with the interior of the crankcase 25 of the engine withwhich the carburetor and fuel ,feeding means is 'used." The pressures inthe engine. crankcase, especially in engines of the two cycle type,

J 'forms an intermediate wall separating the chambers 127' r as follows:

"fuel chamber 129 is'reduced, this action forcing .liquid' carburetordiaphragm 32. The circular chamber is vented to the atmosphereby meansof a passage or vent 157 which communicates with the circular chamber155 through a vertically disposed connecting duct 158 shown in Figure19.

The pump body component ject through openings 151 formed in thediaphragm 118, the'projections being'received'in sockets or bores 162formed in the pump body component 101. The pin and socket arrangementprovides means for properly retaining the diaphragm 118 and the pumpbody mem bers 100 and 1411 in properrelationship. V. r

The operation of thefuel feed or pumping means is carburetor chamber 30,'the' varying pressures in the crank case of the engine with which thecarburetor is used are transmitted through the ducts or passages 133,132 and 131 to vary the pressure in the pumping chamher 127. 'Thevarying pressures in chamber 127 cause reciprocating or pumpingmovements of the diaphragm 11S. When the diaphragm" 118 is flexeddownwardly, V as viewed in Figure 13 by reason of an increase inpressure in the pumping chamber 127, the volume of the fuel in thechamber 129 past the valve 138 through the during each revolution ofthe'engine'crankshaft. The varying pressures existent in theenginecrankcase during engine operation are coma e V or member 100 is prolvided with circumferentially spaced pins 160 which pro- Assuming thatthe fuel flow control valve" 9% shown in Figure 6in the carburetor body10 is moved from its seat to facilitate flow of liquid fuel into the arecess 150 shown in Figure 15 through the outlet152 and passages'94 and93 in the carburetor body shown in Figure 6 to a zone adjacent the valve91. When the valve is open the fuel flows into the carburetor fuelpassage or chamber 30.

Upon fiexure of the pumping diaphragm 118 upwardly as viewed in Figure13 when the pressure in the engine crank case is reduced, the volume ofthe fuel chamber 129 is increased, causing fuel to flow from the fuelstrainer chamber 115 through port 143, recess 146, through the port 148and into the fuel chamber 129 of the pumping means. Upon succeedingflexure of diaphragm 113 downwardly the fuel in chamber 129 is againforced past the valve 138 and into the carburetor through the passageshereina'bove mentioned.

This pumping action of diaphragm 118 continues dur ing the period thatthe valve 96 in the carburetor is in open position to permit flow offuel into the diaphragm chamber 38 of the carburetor. When the fuelrequirements of chamber 31 have been satisfied and valve 90 is in closedposition, fuel pressure is maintained in the ducts or passages leadingfrom the fuel chamber 129 to the zone adjacent the fuel flow controlvalve 90, but

further flexure of the diaphragm 118 ceases because fuel pressure in thechamber is sufiicient to close the valve 9%) and further pumping of fuelfrom chamber 129 ceases.

Figures 10, 11 and 12 are bottom plan views of the carburetor body withthe diaphragm 32 removed and certain portions shown in section. Thesefigures are illustrative of three different forms of fuel conveyingchannel and fuel metering or regulating means for delivering fuel fromthe diaphragm chamber 30 to the main nozzle for normal engine operationand to the idling and low speed orifices for idling and low speed engineoperation.

In the form shown in Figure 10 the carburetor body is provided withspaced transversely arranged passages 17) and 172. Disposed in thepassage 170 is a valve member or valve body 174 having a needle or coneshaped valve portion 175, the valve body 174 being formed with athreaded portion 176 adapted for engagement with a threaded zone of thepassage 170. Disposed in the passage 172 is a'valve member or body 178having a cone shaped or needle valve portion 179, the valve body beingprovided with a threaded portion 180 which engages a threaded zone ofthe passage 178.

The passage 170 receives fuel from chamber 30 through a passage 182, andpassage 172 receives from chamber 30 through a passage 134. The needlevalve 175 extends into a restricted passage 186 which conveys fuel frompassage 30 to the idling orifice i and the low speed orifice 52. Theneedle valve portion 179 valve body 173 extends into and cooperates witha restricted passage 188 for regulating or metering the flow of liquidfuel to the main nozzle or orifice 48 and into the mixing passage 12.

The arrangement of fuel passage and metering means shown in Figure isparticularly adaptable for use with a gravity fuel feed arrangement fordelivering fuel from a supply tank through the tube 98 to the carburetorarrangement shown in Figures 5 and 6.

Figure 11 illustrates another arrangement of fuel channels and meteringmeans for conveying and controlling fuel fiow from the diaphragm chamber39 to the main nozzle or orifice 48 and the idling and low speedorifices. In this form the fuel to be delivered through the main orificeand idling and low speed orifices is conveyed from the chamber 36through a single channel 199. As illustrated in Figure 11 the passage172 is in communication with the recess 72 formed in the upper wall ofchamber 30 by means of the restricted channel or passage 199 and thefuel delivered to the main and low speed and idling orifice flowsthrough this channel.

The passages 170 and 172 are in communication with each other throughthe medium of a drilled passage 192, the entrance of the drilled passage192 being closed by means of a plug or swaged shot 194. Thecross-sectional area of the drilled passage 1% is of comparatively smallarea presenting a restricted fuel passage. It has been found that theliquid seal can be controlled in the calibration of the passagesproviding sufficient strength so that the seal will not be disrupted orimpaired by the reduced pressure in the diaphragm chamber yet not ofsuch high value as to cause undue response or laggard delivery of fuelthrough the nozzle.

The .valve members 174 and 178 are adjustable in the same manner asillustrated in'Figure 10. It should be noted that in Figures 10 and 11the fuel regulating or controlling valves or valve members 174 and 178are accessible from the side of the carburetor body. In some engine andcarburetor installations, due to the presence of other elements orcomponents utilized with the engine construction, it is impracticable toobtain access to needle valve members when they are positioned as shownin Figures l0 and 11.

Figure 12 is illustrative of fuel metering or controlling means for themain orifice and the idling and low speed orifices accessible adjacentthe air inlet zone of the mixing passage in the carburetor. in thisarrangement a passage 2% accommodates a needle valve or metering valvemember 2G2 having a needle or cone shaped valve portion 2&4 adapted forcooperation with a restricted passage 266.

The restricted passage 2% establishes communication between the passage291) and the recess 72 of the fuel chamber 30. The main fuel orifice 48is in communication with the passage 2% by means of a restricted ductorpassage 208. In this form, the passage 172, which in the other formsis in communication with the main orifice 43, is plugged or blocked byan impediment or sealing means 21a).

The carburetor body in this form is provided with a passage 212 arrangedto receive and accommodate an adjustable valve member 214 having aneedle shaped valve portion 216 arranged for cooperation with arestricted duct or passage 213 which leads into or communicates with thepassage 17%. The entrance zones of both passages 176 and 172 are closedby plugs 215. The passage is in communication with the auxiliary chamber53 adjacent the idling and low speed orifices 50 and 52 by means of therestricted passage 186.

The auxiliary chamber 53 adjacent the low speed and idling speedorifices is separated from the chamber 35 by means of a closure or plug55 shown in Figure 5. The fuel for delivery into the mixing passagethrough the idling and low speed orifices 5t) and 52 flows from therecess 72 in the chamber 33 through the restricted passage 199 throughthe intersecting passages 172 and 21;? past the metering needle or valve216 through the restricted passage 213 through passages 17%) and 186into the auxiliary'fuel chamber 53. The fuel for delivery from the mainnozzle 43 flows from the recess 72 through ,the restricted passage 2%past the needle valve 2% and through the restricted passage 2% into themain fuel discharge outlet or nozzle 48.

Heretofore it has been a practice to provide a ball check valve or othermechanical valve means associated with the main nozzle fuel deliveryarrangement in order to prevent air from the mixing passage bleedingback through the main nozzle when the low speed or idling fuel deliveryarrangement or system is in operation. The admission or bleeding of airnullifies the aspiration effect on the diaphragm and impairs orinterrupts fuel flow into the diaphragm chamber 3%} as well as admittingair instead of fuel to enter the idling system causing immediatestoppage of fuel delivery in the idling system.

In the charge forming device or carburetor of the present invention, theball valve or other mechnical valve blocking or sealing means iseliminated and the fuel an effective liquid seal. 7

controlled so that the requirements of strength channels and meteringmeans and other components of arrangement whereby a liquid seal is'established or set up, provided by the liquid fuel in. the passages. Inthe present arrangement the capillary action and surface tension of theliquid fuel is utilized in a manner to estabf lish an eflectiveseal forthe above mentioned purposes.

' The dimensions of several components of the construction and'themaintenance of pressures within certain limits are factors. contributingto thesuccessful operationof the carburetor. To enable a clear.understanding of the invention, reference is directed to Figure 9 whichis of schematic character illustrating the components and factors whichestablish, affect or control the maintenance of In Figure 9, A indicatesthe restricted passage 18 shown in Figures 10 and 11 and the restrictedpassage 206 in Figure 12, B indicates the annular space surroundingtheneedle valve portion of the metering needles or valves for meteringor regulating fuel flow to the main nozzle 48, C indicates the passagezone of the main ori:

lice and D indicates the outlet zone of the main orifice 48 opening intothe mixing passage 12. E indicates the entrance of the passage A openinginto the recess 72 of the diaphragm chamber 30.

Distance F indicates the length of the lever arm from the supporting'pin75 of the lever 74 to the pointof engagement of the'member 80 of thediaphragm assembly with the 'lever arm .81. short lever arm between theaxis of pin-75 and the axis of the inlet valve member 88. K indicates.the vertical distance between the outlet D of the main orifice 48 andthe axis of the needle valve employed for regulating or rnetering fuelflow from the diaphragm chamber to the; main orifice.

J indicates the vertical distance between the plane of the'outlet D ofthe main nozzle and the axis of the metering valve means for metering orregulating the flow of liquid fuel from the diaphragm chamber 30 to theidling and low speed orifices 59 and 52. L indicates, the verticaldistance from thernain orifice outlet D to the upper wall of the recess72 in communication with the diaphragm chamber 30.. I indicates thevertical distance from the outlet D of the main 'orifi'ce to the normalplane;

of the diaphragm 32 of the carburetor construction.

It is found that the effectiveness of'the liquidfuel seal against inwardor reverse flow of air from the. mixing passage through the main nozzle48 between the points D to E in Figure 9 involves or is dependent upon.the capillary meniscus or surface tension cappingpeftectpat the outlet Dof the main nozzle, the frictional liquid resistance in'the passage C,liquid resistance, a capillary seal setup or establishedat the annularzone'B surrounding the metering valve for the main nozzle and the liquidresistance provided by the restricted passage A. It has been found thatthe factors such as the diameter, length and'contours of these liquidpassages may be fashioned and the metering means adjusted or controlledto increase or decrease the combined or overall resistance to liquidflow and secure the sealing or check valve effect that is necessary tothe successful operation of the carbureton.

, It is to be understood that the combined or overall liquid resistancebetween zones A and B must be kept within the calibration limitsnecessary for the delivery of therequisite amount of fuel through themain nozzle 48 forjnormal carburetor requirements during normal engineoperation and hence allied or associated factors or elements in thecarburetor must be. arranged, calibratedand liquid seal can bemaintained.

larticular attention must be; made in respect of the. finite dimensionsof other components of the carburetor construction. 7 'One of theprimary, factors contributing to the successful operationiof thecarburetor is to estab G indicates the length of the of the theconstruction-are of }such a size and of a-particular 'lish' delivery ofinto the mixing passage the I value ofisubatmospheric pressure, that is,with 1 aPinin'imum of lift distance betwen the'fu'el chamber orrjelementslin orderj to obtain successful operation. 'With passage 30and the outlet zone D of the main nozzle.

Certain mechanical components. of' the arrangement .must be properlydimensioned and correlatedwith other ,particularjreference to thecontrol systemforjegulating 'fuel fiowfrom a supplyinto the carburetorfuel chamber 30, the spring 83. hearing against the lever member74 -mustnecessarily exert sufiicient pressure on the inlet ,needlevalve member83 to close' the valve portion 90 l i 1 thereof against 'severalpounds'per square inch'of fuel pressure so as to prevent uncontrolled flooding.of. the

carburetor.

V In practice it has been found that the spring 83v should exertexpansive force-so that it'will effectively close the inlet needle valveagainst-a pressure of approximately I ten pounds per square inch.However, the greater the expansive pressure or forceof the spring 83,the greater 'thesubatmospheric or reduced pressure in 'the'chamber 30will berequired to overcome the force of the spring and dimensionsorldistances indicated'atK, J and'L should be maintained at a minimumfor most successful operation of the arrangement. "The dimension ordistance I indicated at Figure 9 being the vertical distance between theorifice outlet D- the plane of the diaphragm. 32 is important becausethis distance determines theweight'of 7 fuel or gravity load on thediaphragm'32.

. 'Hence, the greater the distance I, the greate r the ad- .versegravity load onthe diaphragm and the greater the subatmospheric orreduced pressure requiredin the diaphragm chamber. tocause the fuel'inlet valve to open; J Operation of thecarburetor at a low atmosphericpressure, that is, a pressure just slightly below atmospheric pressure,in the chamber 30 is essential in order not to fracture or break the.liquid seal in ,the main nozzle de- "livery system under enginesidlingorlow speedrconditions and hence thedistance or dimension I must bereduced to a minimum insofar as possible consistent with the dimensionsof other related components of thecarburetor construction- V It is alsoimportant that the distance I" be kept toa minimum value in order toattain successful operation of the carburetor in inverted position. Itshouldbe noted that in the normal position'of operation of thecarburetor,

' functions as a negative head and resists or tends to retard fuel flowthrough the mainnozzle into the mixing pas-V sage.

' nozzle system or theidleand low speed fuel delivery It is therefore.apparent that thedistances or I that is, with the mixing passagedisposed above the diaphragm 32, fuel height substantially equal todistance I However, when the carburetor 'is the distance or dimension Ibecomes a positive head of fuel and encourages fuelfiow through eitherthe main system.

7 dimensions indicated by I, J, K and L, and thevolume of liquid fuel inthe fuel chamber fifl be maintained at a minimum, actuallyapproachiugzero as an ideal condition in order to provide'a carburetor which is asposition a free as possible and to require a minimum of strength of.seal, that-is, the strength of theliquid sealbetween the zones orpoints D and E indicated on Figure 9.

should be fashioned f so'as to provide a minimum lift factor betweenthe. outlet D of the main orifice and the plane of the diaphragm 32 ininverted position,

13 A practical example of carburetor construction embodying theinvention which has been found to operate successfully in carrying outthe :aethod of the invention includes dimensions as follows:

Dimension I is thirteen thirty-seconds of an inch, Dimension 3 is threesixteenths of an inch, Dimension K is elevent sixty-fourths of an inch,and Dimension L is five sixteenths of an inch.

In the carburetor construction embodying these distances or dimensions,the subatrnospheric pressure within the diaphragm chamber 39 undersubstantially alloperating conditions of the engine is approximatelyconstant and is of a pressure adapted to support a column of Water aboutthree-eighths of an inch in height.

It has been found that this value of subatmospheric pressure is existentat substantially all speeds and loads where the fuel supply is at apressure of several pounds per square inch, but may increase at highspeeds if the fuel supply is a low-gravity head. A relativelyv highsubatmospheric pressure in the chamber 30 does not impair operation athigh speeds as the main nozzle is in full operation and no seal isrequired while it is delivering fuel into the mixing passage.

Figure 25 illustrates the typical relative sizes of fuel adjusting valveor needle 170 and the fuel passage A cooperating therewith in one sizeof carburetor of the invention. The bore A, which corresponds to passage188 in Figures 10 and 11 and passage 296 in Figure 12, is forty-twothousandths of an inch in diameter. Portion 170a is three thirty secondsof an inch in diameter, and the needle portion 17% is formed with ataper, the included angle being about 20. The threaded portion 1700 isformed with thirty-two threads per inch.

It has also been found that in a carburetor embodying the dimensionsabove mentioned, the strength of the liquid seal is maintained Withoutfracture or disruption at pressures supporting a water column up toabout one inch in height. This variation in strength of the liquid sealis dependent in a measure upon the sizes of orifices and fuel passagesrequired for calibration adapting the carburetor to different engines,temperature conditions and variations, and the ratio of the amount oflubricating oil to liquid fuel, a mixture usually used in operatingengines of the two cycle type.

Figure 24 illustrates graphically actual tests of the strength,magnitude or amplitude of the seal established orinfluenced by certainstructural factors in a carburetor embodying the principles of thepresent invention.

The upper chart illustrates graphically the strength of the seal inproportion to variations in size of the bore of the main nozzle ordischarge orifice. The bore size, indicated along the horizontalco-ordinate, is expressed in hundredths inches and the verticalco-ordinate indicates the negative pressure expressed in inches ofwater.

The curve XX in the upper chart of Figure 24 indicates the variation inthe strength of the capillary seal in the carburetor, the curveindicating the pressure expressed in inches of water at which the sealbecomes broken or ineffective. For example, the point P on the curve XXis the intersection of the co-ordinates for a bore of forty-sixthousandths of an inch and shows that the seal will not be broken orrendered ineffective until the pressure slightly exceeds that requiredto support a column of water approximately one and one sixteenth inchesin height.

The broken line AA in each of the graphs indicates the negative pressureor pressure below atmospheric pressure efiective in the diaphragmchamber or passage. The line AA shows that the negative pressure is thatrequired to support a column of water approximately three-eighths of aninch in height. It has also been found as shown in the graphs, that thisoperating pressure is substantially i4; constant throughout variousspeeds of the engine with which the carburetor may be used.

The center graph of Figure 24 illustrates the effectiveness or zones offracture of the seal in the passage containing the main adjustingneedle-valve and illustrates the efiect upon the seal with variousdegrees of opening of the needle valve in its passage. In the carburetorutilized in formulating the data on the graphs, the nozzle bore is of adiameter of 56 drill, being forty-six thousandths of an inch, and thefuel supply passage from the diaphragm chamber to the fuel supply needleis the diameter of a number 66 drill, viz. forty thousandths of an inchin diameter. The horizontal co-ordinate represents the proportionateamounts of opening of the main fuel adjusting needle. For example, withthe main adjustment opened one-half turn, the point P on the curve YY,indicates the pressure at which the seal will be broken or disrupted,and this will occur at a pressure slightly above the pressure requiredto support a column of water approximately one and one-eighth inches inheight.

As the line YY indicates the depression in pressure of the carburetor inactual operation, it will be seen that the seal will be elfective up toa pressure which will support a column of water one inch in height.

The normal adjustment of the main needle valve of the carburetor is fromthree-quarters of a turn to one turn toward open position as theoperating range identified by the line T. From further examination ofthe center graph of Figure 24, it will be noted that when the mainadjustment is opened a full turn, the capillary seal will not be brokenor impaired until the pressure exceeds that required to support a columnof water approximately one inch in height, which is indicated by thepoint S.

The lower graph on Figure 24 illustrates the effect of various sizes offuel supply passage leading from the diaphragm chamber to the borecontaining the main fuel adjusting needle or valve. curve indicates the.pressures at which the seal will be broken or fractured with varyingsizes of fuel supply passage. For example, the point V indicates themaximum strength of the capillary seal with a fuel passage of fortythousandths of an inch in diameter. A pressure slightly exceeding thatwhich will support one inch of water would fracture or break thecapillary seal. t should be noted that the smaller the diameter of fuelsupply passage, the greater the pressure required to break the seal.Tins pressure decreases rapidly upon an increase in diameter of thepassage, the strength curve of the seal being indicated by the line ZZ.

it should be noted from the graphs that the strength of the capillaryseal in the carburetor in all operating ranges of the carburetor is wellabove the depression pressure operative in the diaphragm chamber duringengine operation. Hence, successful operation of the carburetor will notbe impaired as far as the capillary seal is concerned until thepressures indicated by the seal strength curves in the graphs becoineless than the operating depression or reduced pressure indicated by thebroken lines AA in Figure 24.

It has been found that the strength of the liquid seal is by natureconsistent and dependable and by reason of this fact, the pressuredifferential between the normal operating pressure in the fuel chamber3% and the pressure required to fracture or disrupt the liquid seal is asufiicient factor of safety and may be relied upon as an effectiveliquid check valve.

It should be further pointed out that the choke band of the Venturi isentirely free of obstruction as the main nozzle outlet is an opening inthe Wall of the choke band, an arrangement eliminating the use of aconventional nozzle or outlet tube extending into the Venturi. Throughthis arrangement, the Venturi operates at a high effici ency and cantherefore be made slightly smaller "is a w in area for the same air flowcapacity or 'for" a given sizeor type of'engine." Thus by providingaVenturi having a high efiiciency factor, a slight aspiration effect 'isappliedltothe liquid seal in themain nozzle under idling conditionswhich gives or imparts some back-drag 'efiectassisting in and atlow'speed or idling conditions.

, It will be apparent from the foregoing description that the presentinvention involves an arrangement wherein certain characteristics of.theliquid fuel "are utilized 'through'a unique combination to obtain anautomatic valve action without the use of mechanical devices of anykind. The incorporation of the liquid valve involves no expense, it isnot subject to wear and is always instantly operable to'perform itsscaling functions without requiring any operation on the part of theuser.

Itfis apparent that, within the scope of the invention, modificationsand different arrangements may be' made other than. is herein disclosed,and the present 'disclosure is illustrative merely, the inventioncomprehending 7 all variations thereof.

I claim: 7 V 1. In combination, a member formed with a fuel chamber, adiaphragm forming a wall'of the fuel chamber, a cover member for thediaphragm adaptedito be securedto the first mentioned member, saiddiaphragm being of uniplanar'shape and formed of flexible material, aplurality. of projections on one of said members, a plurality ofopenings formed in the diaphragm adapted to receive the projections, theopenings in'the. diaphragm being normally out of, registry with theprojections on the member whereby registry of the. openings in thediaphragm with ,the projections in assembly stresses the material of thediaphragm radially inwardly to facili tate flexing movements of thediaphragm} 2. In combination, a body member formed with a "chamber, adiaphragm forming a wall of the chamber, [a cover member for thediaphragm adapted to be secured to "the bodymemb'er, saiddiaphragm beingof planar shape and formed of substantially inelastic flexible ma-'terial, raised portions on one of said members, said diaphragm beingformed with openings adapted to receive the raised portions, theopenings in the diaphragm being normally out of registry with the raisedportions on the member whereby in assembly registry of the openings inthe diaphragm with the raised portions stresses the material of thediaphragm radially inwardly to facilitete flexing movements of'thediaphragm.

3. In combination, charge forming apparatus including a body formed witha mixing passage, a fuel chamber formed in the body in close proximityto the mixing passage, a flexible diaphragm forming a wall'of the fuelchamber, an orifice in the mixing passage, a fuel inlet for, the fuelchamber, said fuel inlet being formed 'with a valve seat, a valve memberhaving a cone-shaped needle portion at one end thereof extending intothe inlet against the pressure of the fuel and cooperating with the seatto regulate fuel flow into the fuel chamber,

'aleverin the fuel chamber fulcrumed on the body, one

arm of the lever being in engagement with the valve member and the otherarm in engagement with the cen- -tral region'of the-diaphragm, saidlever arms being of different lengths wherebyfforce applied by movementof the diaphragm'to the lever is multiplied through the V lever toactuate the valve member in the fuel inlet duct,

a spring engaging the lever at a regionbetween the fu'lcrum and the zoneof'engagement of the diaphragm with the lever and adjacent the. fulcrum,said fuel chamber being unvented whereby said diaphragm is actuated fuelchamberbeing unvented, a fuel duct formed in the :body,.a fuel controlvalve having a needle ,portion;ex-

tending into the duct against the incoming fuel: and ef- V rectiv'e uponan' increase in pressure in thechamber to .close the duct, aleverfulcrumed'within theehamberand". 'having portions engaging the fuelinlet valve and "they ,dia'phragmjspring means normally biasing saidinlet valve toward closed position, a restricted fuel metering 5 ingpassage, and a restricted fuel conveying duct in communication with thefuel chamberand the orifice 4. In combination, a chargeforming devicefor an internal combustion engine including a body formed with a mixingpassage, a shallow fuel receiving cham bar formed in the body, aflexible diaphragm forming a wall of the chamber, a channel formedin:saidbody having an orifice in the form of an opening in the Wall ofthe mixing passage arranged to deliver liquid fuel from the chamberintothe mixing passage under the influence of subatmospheric pressure inthe mixing passage, said fuel chamberbeing-unvented, a fuel inlet ductformed in the body,'a fuelcontrol valve having a needle portionextending into the duct against the incoming fuel and effective upon anincrease in pressure in thefchamber to close'the duct, .a leverfulcrumedwithinfthe chamber and having portions engaging the fuel inletvalve and the diaphragm, spring means normally biasing said. inlet'valve toward closed position, a restricted fuel metering passageestablishing communication between the fuel chamber and the orifice. in:the mixing passage, 'said diaphragm'being disposedrelative to saidopening in said mixing passage within a maximum distance as determinedby the capillary. effect of the fuel orificefin the form of anlopeningin the/wall of the'rhix- I ing passage arranged to deliver liquid fuelfroin 'the.

chamberfinto, the mixing passageunder the influence of sub-atmosphericpressure in t he mixing. passage, said passage establishingcommunication 'between the fuel chamber and the orifice inthemixingpassage, said orifice of said channel being in that region ofthe wall of. the mixing passage nearest the diaphragm, said diaphragmbeing disposed relative to said opening in said mixing passage within amaximum .distance asdetermined by the capillary effect of the fuel'insaid metering passage, said maximum distance being that distance atwhich the capillary effect of said fuel in said meteringpassage will Imaintain said fuel in said passage againsta pressuredifferentialequivalent to that pressure required to support a column of water aboutone inch inheight 6. In combination,- a charge forming device for aninternal combustion engine including a body formed with a mixingpassage,a shallow fuel receiving chamberformed in the bodyfa flexible diaphragmforming a wall ofthe chamber, a channel formed in said bodyhaving'anorifice in the form of an opening in the wall of the mixing passagearranged to deliver liquid fuel froin the chamber into the-mixingpassage funder the influence of subatmosphericpressure in the mixingpassage, said fuel chamber beingiunvented, a fuel inlet duct formed inthe body,

, a fuel control valve cooperating with the duct effective" upon anincrease in pressure in the chamber. to close the duct, aileverfulcrumedwithin the chamber and having portions engaging the fuel inlet valve andthe diaphragm,

spring means normally biasing said inlet valve toward closed position, arestricted fuel metering passage establishing communication between thefuel chamber and the orifice in the mixing passage, said diaphragm beingdisposed relative to said opening in said mixing passage within amaximum distance as determined by the capillary effect of the fuel insaid metering passage, said maximum distance being that distance atwhich the capillary effect of said fuel in said metering passage willmaintain said fuel in said passage against a pressure differentialequivalent to that pressure required to support a column of water aboutone inch in height.

7. In combination, a charge forming device for an internal combustionengine including a body formed with a mixing passage provided with aVenturi, a shallow fuel receiving chamber formed in the body, a flexiblediaphragm forming a wall of the chamber, a channel formed in said bodyhaving an outlet in the Wall of the Venturi without obstructing theVenturi passage arranged to deliver liquid fuel from the chamber intothe Venturi under the influence of subatmospheric pressure in the mixingpassage, said fuel chamber being unvented, a fuel inlet duct formed inthe body, a fuel control valve cooperating with the inlet duct effectiveupon an increase in pressure in the chamber to close the duct, a leverfulcrumed within the chamber and having portions engaging the fuel inletvalve and the diaphragm, spring means normally biasing said inlet valvetoward closed position, a restricted fuel metering passage establishingcommunication between the fuel chamber and the outlet into the Venturi,said diaphragm being disposed relative to said opening in said mixingpassage within a maximum distance as determined by the capillary eflectof the fuel in said metering passage, said maximum distance being thatdistance at which the capillary efiect of said fuel in said meteringpassage will maintain said fuel in said passage against a pressuredifferential equivalent to that pressure required to support a column ofwater about one inch in height.

8. In combination, charge forming apparatus as in claim 3 and having asecondary outlet in a wall of the mixing passage communicating with saidchamber for supplying fuel to the mixing passage for idling operation.

9. In combination, charge forming apparatus as in claim 4 and having asecondary outlet in a wall of the mixing passage communicating with saidchamber for supplying fuel to the mixing passage for idling operation.

10. In combination, charge forming apparatus as in claim 5 and having asecondary outlet in a wall of the mixing passage communicating with saidchamber for supplying fuel to the mixing passage for idling operation.

11. In combination, charge forming apparatus as in claim 6 and having asecondary outlet in a wall of the mixing passage communicating with saidchamber for supplying fuel to the mixing passage for idling operation.

12. In combination, charge forming apparatus as in claim 7 and having asecondary outlet in a wall of the mixing passage communicating with saidchamber for supplying fuel to the mixing passage for idling operation.

13. In combination, charge forming apparatus as in claim 3 and whereinthe fuel conveying duct includes a constricted portion of a diameter ofbetween about 0.03 and 0.10 inch.

14. in combination, a charge forming device as in claim 4 and whereinthe fuel metering passage includes a constricted portion having adiameter of between about 0.03 and 0.10 inch, and a second constrictedportion having a diameter of between about 0.02 and 0.07 inch.

15. in combination, a charge forming device as in claim 5 and whereinthe fuel metering passage includes a plurality of constricted portionsincluding a first constricted portion having a diameter of between about0.03 and 0.10 inch, a second constricted portion having a diameter ofbetween about 0.02 and 0.07 inch, and a third constricted portioncomprising an adjustable needle valve in said passage.

16. In combination, a charge forming device as in claim 6 and whereinthe fuel metering passage includes a constriction comprising anadjustable needle valve in said passage.

17. In combination, a charge forming device as in claim 7 and whereinsaid restricted fuel metering passage comprises a plurality ofconstricted portions including a first constricted portion having adiameter of between about 0.03 and 0.10 inch, a second constrictedportion having a diameter of between about 0.02 and 0.07 inch, and athird constricted portion comprising an adjustable needle valve in saidpassage.

References Cited in the file of this patent UNITED STATES PATENTS2,033,354 Pennington Mar. 10, 1936 2,422,529 Cofiey June 17, 19472,632,475 Elo Mar. 24, 1953 2,642,090 Barr June 16, 1953 2,674,443Bracke Apr. 6, 1954 2,678,065 Crookston May 11, 1954 2,688,342 Kehrer etal. Sept. 7, 1954 2,712,928 Winkler et al. July 12, 1955 2,713,854Conover July 26, 1955 2,724,584 Armstrong Nov. 22, 1955 2,733,902Phillips Feb. 7, 1956 2,768,819 Bodine Oct. 30, 1956 2,774,582 BrackeDec. 18, 1956 @isciaimm' 53.??ARAT'U TOlQdO, Ohio.

COMBUSTION ENGINE.

s FOR DELIVERING Patent (W03 6. Phillz'os 2,81,372.-B em COMBUSTIBLEMIX'FJRE TO AN INTERNAL 958. Dlsclalmer fiiecL Flov. 23, 196:2, by theasslgnee,

dated July 1, y

The Tz'ZZotson Z'vl'cmufactuwing GOC'HPCZ'TLy. Hereby enters thisdisclaimer to claims 3, 8

[Oyficz'al Gazette J cmumy 1, 1963.]

and 13 of said Patent.

